According to TV station NHK, 30 year-old Yusuke Katayama was picked up after Tokyo police accessed CCTV pictures that showed the accused near the animal not long before the memory card was retrieved from its collar.

Katayama is alleged to have issued bomb threats against schools in the last six months, hijacking the PCs of uninvolved people using a Trojan in order to hide the origin of the messages.

It later emerged that police had attempted to coerce confessions from four of the innocent suspects which led to a hugely embarrassing climbdown when they were shown to be uninvolved.

Disturbing messages were also received by a lawyer in Tokyo and a TV station threatening suicide, backed up by a picture of an anime doll inside a noose made from Ethernet cable.

Finally in January of this year, the media received a message explaining that further clues would be sent to the police on an SD card attached to a cat's collar. This turned out to contain the source code for the remote-control Trojan used to compromise the PCs.

The motivation for the bizarre campaign appears to be resentment against the police and a desire to embarrass them at every turn.

Why police took so long to trace the accused might be an even bigger mystery; Japanese media reports Katayama as having a conviction for a similar unspecified crime in 2006.